The present invention relates to novel cephalosporin derivatives and their crystalline form, processes for producing them, and to pharmaceutical compositions containing them for treating and/or preventing infectious diseases.
Developments of cephalosporin derivatives have been remarkable. Some cephalosporin derivatives have been developed which have excellent antibacterial activity against Gram-negative bacteria including Pseudomonas aeruginosa. However, the antibacterial activity of these cephalosporin derivatives is rather poor against Gram-positive bacteria. Several cephalosporin antibiotics have been used for the treatment of Gram-positive bacteria infections and the increase of Gram-positive bacteria resistant to cephalosporin antibiotics, for example, methicillin-resistant Staphylococcus aureus (MRSA), has become widely known year by year.
From the foregoing background, it has been desired to develop cephalosporin derivatives having a strong antibacterial activity against Gram-positive bacteria while retaining a sufficient antibacterial activity against Gram-negative bacteria including Pseudomonas aeruginosa.